The use of stents in bodily lumen is well known. A stent is typically delivered in an unexpanded state to a desired location in a bodily lumen and then expanded. The stent may be expanded via the use of mechanical device such as a balloon or the stent may be self-expanding.
Because a stent often must be delivered through tortuous anatomy, it is desirable for the stent to be flexible. It is also desirable for the stent to exhibit high scaffolding in the expanded state. In general, however, as stent flexibility is increased, scaffolding is decreased and similarly, as scaffolding is increased, flexibility is decreased.
There remains a need for a stent having a high degree of flexibility in the unexpanded state and high scaffolding in the expanded state.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
The invention in various of its embodiment is summarized below. Additional details of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
In one embodiment, the invention is directed to stents comprising a plurality of interconnected cells where at least one of the interconnected cells is a lockable cell. The lockable cell includes a first locking member and a second locking member disposed opposite the first member. The first and second locking members are movable between a first position in which they do not lock with one another to a position in which they lock with one another.
The first locking member may be a pincer member comprising a first arm and a second arm and the second locking member may be a tongue. The first and second arms are movable between a first position in which they do not grip the tongue and a second position in which they grip the tongue. Desirably, the pincer members are directly opposite the tongues. Also desirably, the first and second arms are in the first position when the stent is in the unexpanded state and in the second position when the stent is in the expanded state. The stent may comprise a plurality of such cells arrangable in rows, columns or any other suitable arrangement. Adjacent lockable cells may have one or more walls in common or may have no walls in common. Individual lockable cells may comprise a single pincer member and tongue or multiple pincer members and tongues. The clampable cell may even include pincer members which are constructed and arranged to clamp other pincer members. The pincer member(s) and tongue(s) may extend from the proximal and distal ends of the cell or vice versa or may extend from sidewalls of the cell extending between the proximal and distal ends of the cells.
The first and second locking members may also be first and second interlocking members which are constructed and arranged to interlock with one another when the cell is locked.
The invention is also directed to stents comprised of a plurality of interconnected bands where at least one of the interconnected bands has a first locking member extending therefrom toward an adjacent band and a second locking member extends from an adjacent band. The first and second locking members are movable from a first position in which they do not lock with one another to a second position in which they lock with one another.
The first locking member may be a pincer member extending from a band toward an adjacent band. The pincer member has a first arm and a second arm. A tongue extends from the adjacent band. The first and second arms are movable between a first position in which they do not grip the tongue and a second position in which they grip the tongue. Desirably, the pincer members are directly opposite the tongues. Also desirably, the first and second arms are in the first position when the stent is in the unexpanded state and in the second position when the stent is in the expanded state. The pincer members and tongues may be placed anywhere along the bands. Desirably, the pincer members extend from peaks on bands and the tongues extend from a troughs on a adjacent bands. At least one pair of adjacent bands has at least one pincer member and one tongue extending therefrom. Additional pincer members and tongues may be provided between adjacent bands. Adjacent bands may include pincer members which grip other pincer members. The bands may desirably be circumferential bands, substantially longitudinal bands or helical bands.
The first and second locking members may also be first and second interlocking members extending from adjacent bands, the interlocking members constructed and arranged to interlock with one another upon locking of the cell.
In another embodiment, the invention is directed to stents comprising a plurality of interconnected cells where at least one of the interconnected cells is a lockable cell. The lockable cell includes a first locking member and a second locking member. The second locking member is constructed and arranged to lockingly engage the first locking member on expansion of the stent. Desirably, the first and second locking members clamp together or interlock with one another.
In yet another embodiment, the invention is directed to stents having a plurality of interconnected bands, where at least one of the interconnected bands has a first locking member extending therefrom toward an adjacent band and where the adjacent band has a second locking member which is constructed and arranged to lockingly engage the first locking member on expansion of the stent. Desirably, the first and second locking members clamp together or interlock with one another. Any suitable type of band may be used in the inventive stents. Desirably, each band is serpentine having alternating peaks and troughs, with the peaks extending in a distal direction and the troughs extending in a proximal direction. Bands having other geometric patterns that provide desirable contraction and expansion properties may be used as well. The bands may desirably be circumferential bands, substantially longitudinal bands or helical bands.